Articles
Hull rot in Australian almond orchards
Article number
1406_46
Pages
319 – 326
Language
English
Abstract
Hull rot of almond is a complex disease that causes direct loss of yield due to infected nuts and downgrading of in-shell nuts, as well as twig dieback and spur death resulting in yield reductions in subsequent years.
Hull rot is commercially important in all production regions of Australia except Western Australia.
Hull rot occurrence begins in January during early hull split, which is the most susceptible stage for infection.
Our research is focused on management strategies for this disease, characterizing the fungus associated with hull rot of almonds in Australia, and reducing the development of hull rot symptoms on almond under field conditions.
Assessment of 19 advanced Australian breeding lines showed material had less hull rot than the industry standard ‘Nonpareil’. Evaluation of an established rootstock trial showed that ‘Nonpareil’ grafted onto Peach Almond (P. persica × P. dulcis) rootstocks, particularly ‘Monegro’, ‘Garnem’, ‘Hansen’ and ‘Felinem’, developed more hull rot than other rootstock choices.
Investigating the influence of water and nitrogen on hull rot over two seasons showed disease severity was reduced with a sustained deficit water schedule of 70%ETc while restricted nitrogen did not influence hull rot.
Fumaric acid analysis of infected ‘Nonpareil’ hulls found high instances in standard water and nitrogen treatments compared to restricted water and nitrogen treatments.
Management trials at hull split found that current chemistry can reduce hull rot but not eliminate the disease. diKaP™ imported from California shows similar efficacy to registered products available in Australia.
A timely application of a protectant product at hull split is beneficial in high-risk hull rot areas.
Hull rot is commercially important in all production regions of Australia except Western Australia.
Hull rot occurrence begins in January during early hull split, which is the most susceptible stage for infection.
Our research is focused on management strategies for this disease, characterizing the fungus associated with hull rot of almonds in Australia, and reducing the development of hull rot symptoms on almond under field conditions.
Assessment of 19 advanced Australian breeding lines showed material had less hull rot than the industry standard ‘Nonpareil’. Evaluation of an established rootstock trial showed that ‘Nonpareil’ grafted onto Peach Almond (P. persica × P. dulcis) rootstocks, particularly ‘Monegro’, ‘Garnem’, ‘Hansen’ and ‘Felinem’, developed more hull rot than other rootstock choices.
Investigating the influence of water and nitrogen on hull rot over two seasons showed disease severity was reduced with a sustained deficit water schedule of 70%ETc while restricted nitrogen did not influence hull rot.
Fumaric acid analysis of infected ‘Nonpareil’ hulls found high instances in standard water and nitrogen treatments compared to restricted water and nitrogen treatments.
Management trials at hull split found that current chemistry can reduce hull rot but not eliminate the disease. diKaP™ imported from California shows similar efficacy to registered products available in Australia.
A timely application of a protectant product at hull split is beneficial in high-risk hull rot areas.
Authors
T.J. Wiechel, P. Faulkner, S. Kreidl, J. Edwards
Keywords
Rhizopus stolonifer, Prunus dulcis, fungicides, rootstock, varietal resistance
Groups involved
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